Narrative:

While switching runways; obtaining new [performance data] we inadvertently took off with flaps set 1 instead of 5. This was my leg to fly. Conditions at the time were light rain; wet runways; gusting and shifting winds. We were also dealing with multiple taxi changes as well as other unusual air traffic control distractions. Events as they unfolded: during taxi to [runway] 8R we noted that aircraft were being asked to take [runway] 12. In anticipation of this the captain had me obtain new [performance data] for a max 26k takeoff for runway 12. Rain; winds; approaching weather as well as multiple go-arounds on runway 9 as we were taxing out justified a max 26k takeoff. When the new [performance data] printed I told the captain we were good for 12 and it was a flaps 5 takeoff. Upon reaching the holding pad for 8R; tower asked us to take runway 12 and switch to that tower frequency. I switched radios; set up the FMC; reset the MCP and navigation display (nd) for runway 12 takeoff. As the captain taxied I read and double checked the [performance data] and FMC aloud. At this time we were at the takeoff briefing portion of the mechanical checklist. I picked up the list from this point as were cleared to line up and wait. The captain asked to verify we were good for 12 and all set. The takeoff acceleration; lift off; and climb out was uneventful. At 1;000 feet I called VNAV cross checked the airspeed just below flaps 1 and called for flaps 1. At this time I heard the captain exclaim... I double checked the airspeed we were accelerating through flaps 1 so I called flaps up. The rest of the climb out and flight was uneventful. I continued the enroute climb with the auto pilot engaged. The captain asked if I specifically remembered reselecting flaps 5 for takeoff. I did not remember doing so. I asked why and that's when he told me we had taken off with flaps 1.I am usually very meticulous with my duties especially when it comes to the FMC and configuration. I can only say that the unique combination of weather; ground and radio congestion; as well as unusual operations (multiple aircraft go-arounds and an aircraft instructed to back taxi into position with multiple aircraft waiting in line for example) contributed to the oversite. From now on my personal technique will be to restart the mechanical checklist from the beginning whenever we have new [performance data] or a runway change from what was anticipated when we completed the before taxi check list.

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Original NASA ASRS Text

Title: B737 flight crew reports departing with the flaps set to 1 while a setting of 5 was required after a runway change.

Narrative: While switching runways; obtaining new [performance data] we inadvertently took off with flaps set 1 instead of 5. This was my leg to fly. Conditions at the time were light rain; wet runways; gusting and shifting winds. We were also dealing with multiple taxi changes as well as other unusual air traffic control distractions. Events as they unfolded: during taxi to [Runway] 8R we noted that aircraft were being asked to take [Runway] 12. In anticipation of this the Captain had me obtain new [performance data] for a max 26k takeoff for Runway 12. Rain; winds; approaching weather as well as multiple go-arounds on Runway 9 as we were taxing out justified a max 26k takeoff. When the new [performance data] printed I told the Captain we were good for 12 and it was a flaps 5 takeoff. Upon reaching the holding pad for 8R; tower asked us to take Runway 12 and switch to that tower frequency. I switched radios; set up the FMC; reset the MCP and Navigation Display (ND) for Runway 12 takeoff. As the Captain taxied I read and double checked the [performance data] and FMC aloud. At this time we were at the takeoff briefing portion of the mechanical checklist. I picked up the list from this point as were cleared to line up and wait. The Captain asked to verify we were good for 12 and all set. The takeoff acceleration; lift off; and climb out was uneventful. At 1;000 feet I called VNAV cross checked the airspeed just below flaps 1 and called for flaps 1. At this time I heard the Captain exclaim... I double checked the airspeed we were accelerating through flaps 1 so I called flaps up. The rest of the climb out and flight was uneventful. I continued the enroute climb with the auto pilot engaged. The Captain asked if I specifically remembered reselecting flaps 5 for takeoff. I did not remember doing so. I asked why and that's when he told me we had taken off with flaps 1.I am usually very meticulous with my duties especially when it comes to the FMC and configuration. I can only say that the unique combination of weather; ground and radio congestion; as well as unusual operations (multiple aircraft go-arounds and an aircraft instructed to back taxi into position with multiple aircraft waiting in line for example) contributed to the oversite. From now on my personal technique will be to restart the mechanical checklist from the beginning whenever we have new [performance data] or a runway change from what was anticipated when we completed the before taxi check list.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.